Field of the Invention
The present invention generally relates to face masks that cover at least one of a nose and a mouth of a user to supply respiratory gas under positive pressure. More particularly, certain aspects of the present invention relate to such masks that have an improved nasal seal portion.
Description of the Related Art
Face masks can be used to provide respiratory gases to a user under positive pressure. In configurations in which both a mouth and a nose of a user are covered, the full face mask typically will overlie a bridge of the nose. Generally, a single seal will circumscribe the nose and the mouth of the user.
Such full face masks commonly are secured to a head of the user with headgear. In order to sufficiently reduce leakage, the headgear typically is tightened, which results in an elevated pressure being exerted on a bridge of a user's nose. As the headgear is tightened, the seal typically applies a progressively increasing load on the bridge of the nose. The pressure can be a source of discomfort and, in some circumstances, can lead to pressure sores over time. Looser fitting headgear may provide greater patient comfort, but air leakage can occur. In particular, loose fitting and in some cases even tight fitting masks can leak air around the portion of the mask near the user's tear ducts and nasal bridge.